The address-electrode width is an important parameter to affect both the address and sustain discharge characteristics in an ac-plasma display panels (ac-PDPs). It was numerically founded that as the address-electrode width was wider, the capacitance between the sustain and address electrodes (=C-AY) increased, but the capacitance between the two sustain electrodes (=C-XY) decreased. The resultant changes in the sustain and address discharge characteristics, such as a firing voltage, discharge delay time, and luminance, were examined in the 50 in ac-PDP with a high Xe (>11%) content. The increase in the address-electrode width caused an increase in the firing voltage between the sustain electrodes, which was mainly due to the decrease in the capacitance between two sustain electrodes and the increase in the wall charges accumulation toward the address electrode. In particular, the luminance was observed to increase with an increase in the address-electrode width. As the address-electrode width became broaden, the sustain discharge path was longer toward the address electrode, thereby enlarging the discharge volume. Therefore, it was observed that the IR (VUV) and Ne emissions were increased considerably. Furthermore, these experimental results were confirmed by simulating the electric field strength and Xe ion distribution in discharge cell with respect to the address-electrode width.